1. Field of the Invention
This invention relates to a door closer.
More particularly, this invention relates to a door closer in which on one hand there is a drive cam disk which is positively and non-positively connected with an output shaft that projects out of a housing that is filled with damping medium, whereby the drive cam disk, viewed in the axial direction of the door closer, is in contact on one hand on each side with a pressure roller, and on the other hand with a spring piston which is pressurized by a closing spring, and is also actively connected with a damping piston.
In other words, there is provided a door closer assembly in which the closing force is exerted by at least one closing spring. The door closer assembly generally comprises a walled housing adapted to be filled with a damping medium, a rotor, journalled for rotation in said housing, with the rotor being configured with at least one output shaft formation which is configured to extend an effective distance from the housing and the rotor also comprising a cam disc formation which is positively and non-positively connected with the output shaft formation that projects out of the housing. There is also included a first piston apparatus slidingly disposed in the housing, a first pressure roller mounted between the rotor and the first piston apparatus adjacent the cam disc formation for rotation in conformity with the rotation of the cam disc formation of the rotor to thereby slidingly displace the first piston apparatus in conformity with the motion of the cam disk formation. There is also provided a second piston apparatus slidingly disposed in the housing and configured to be pressurized by the closing spring, and a second pressure roller mounted between the rotor and the second piston apparatus for rotation in conformity with the rotation of the cam disc formation of the rotor to thereby slidingly displace the second piston apparatus in conformity with the motion of the cam disc formation.
In accordance with one feature of the invention at least one of the first and second piston apparatus is disposed in the housing adjacent to the rotor to provide at least two chambers for receiving damping fluid in the housing, with suitable valve devices being part of the piston apparatus.
Thus, at least one of the first and second piston apparatus is configured to provide flow of damping medium between the first and second chambers of the housing.
In accordance with one feature of the invention the housing, the rotor, the first and second piston apparatus, and the first and second pressure rollers are made of the same material of construction and exhibit at least substantially the same thermal expansion coefficient.
The piston and the housing can be made of an oil-tight material of construction, such as plastic.
The invention also relates to a door closer with a plastic piston that has an internal gearing, which plastic piston is driven by means of a pinion that is fastened positively and non-positively on an output shaft, whereby the output shaft projects at least on one side out of a housing that encloses the piston and a closing spring.
The invention further relates to the method of substantially automatically shaping the component structures of a door closer assembly.
2. Background Information
Door closers are well known in the art.
A generic door closer that represents the known art in one aspect is disclosed by Swiss Patent No. 281,690, hereby incorporated as by reference as if set forth in its entirety herein, wherein the drive cam disk, viewed in the axial direction of the door closer, is in contact on each side with a pressure roller. The door closer described in Swiss Patent No. 281,690, hereby incorporated by reference as if set forth in its entirety herein, can be used for DIN (German Industrial Standard) left-hand doors and DIN (German Industrial Standard) right-hand doors, whereby an output shaft is equipped with a symmetrically realized cam disk, which is in contact with the piston and thus with the closing spring. Both the housing and the piston are made of an oil-tight plastic.
A generic door closer that represents the known art in another aspect is disclosed in German Utility Model No. G 94 13 039 U1, hereby incorporated by reference as if set forth in its entirety herein, which describes a door closer which reproduces the internal gearing in a piston. In this case, the gearing and the piston are realized in the form of separate components, whereby the gearing is preferably made of a material other than plastic, namely of a material other than the material of which the piston is made. Likewise, at least portions of the pinion that is engaged with the gearing are made partly of metal and plastic.
German Patent No. 40 02 889 A1, hereby incorporated by reference as if set forth in its entirety herein, describes a door closer, the housing of which is realized in the form of a profile with a hollow chamber. This hollow chamber profile is realized in one piece and consists of an extruded profile which is made of an aluminum alloy or plastic.
A damping piston which is composed of a solid body and an elastic elastomer or plastic body connected with said solid body is described in German Laid Open Patent Publication No. DE-AS 10 39 886, hereby incorporated by reference as if set forth in its entirety herein.
A piston that consists of external gearing in the form of an inserted toothed rack or toothed rod which is made of metal or plastic is described in U.S. Pat. No. 4,019,220, hereby incorporated by reference as if set forth in its entirety herein.
The object of the of the invention is to manufacture a lightweight, economical door closer, in which the machining that is otherwise necessary can be eliminated.
The present invention teaches that this object can be accomplished by a door closer and method of making a door closer as specified hereinbelow and in the appended claims.
To reduce costs, the invention teaches that, in addition to the parts that the known art discloses can be made of plastic, all the parts requiring intensive machining are made of plastic. These parts include in particular the damping piston, the spring piston and the housing, the drive cam disk, the output shaft and/or the pressure rollers that interact with the drive cam disk. The invention also teaches that the parts located outside the door closer, such as a pantograph-type linkage or actuator arm on a slide rail door closer in connection with the glide rail, all be made out of plastic. It does not matter whether the door closer in question is a floor-mounted door closer, frame-mounted door closer or an internal door closer, i.e., a door closer secured to the inner face of the door, for example.
The cylinder walls that surround the piston are generally round. The reason for this shape is related in particular to the finishing and machining operations that can thereby be eliminated, because the round shape is the easiest to manufacture. However, if the objective is to manufacture a small, economical door closer, i.e., a door closer that does not take up a great deal of space, or in other words, is not required to absorb heavy loads, the cross section of the piston, i.e., of the damping piston and of the spring piston and/or the plastic piston with gearing, can have a cross section other than a round one, namely an oval, rectangular, square or quadrangular cross section. All these shapes can easily be fabricated in plastic, because the housings and/or pistons are manufactured using injection molding processes. On the basis of the characteristics of the plastics currently available, these processes have an enormous dimensional tolerance and thus guarantee an exact fit.
For example, it is possible to manufacture, at no extra cost, door closers as disclosed in German Patent No. 35 45 314 C2 and in German Patent No. 36 45 315 C2 out of plastic, in which the teeth of the piston gearing have different sizes and a different modulus. The matching gearing on the output shaft which is engaged with this gearing can also be easily made of plastic.
A housing of the type described above, on account of the geometric cross sections, need not necessarily be manufactured in one piece using the injection molding process. The housing can also be manufactured from a plurality of segments or partial segments. These segments or partial segments are assembled or combined by means of molded tabs or lugs and corresponding depressions in the matching or mating part, and are positively or non-positively permanently connected together by appropriate methods such as gluing, ultrasonic welding, laser welding or similar processes. As a result of these methods, the dimensional stability of the individual segments is preserved. At the same time, when the housing is realized in the form of individual segments, it is also possible to create channels, borings, pockets, valve seats or even valves themselves directly in the manufacturing process without the need for finishing processes, which reduces the time and effort and thus the cost of manufacture.
Conventionally, the ends of door closers are closed by caps or closures, and depending on the manner in which the segment is manufactured, the invention teaches that these caps or closures are no longer absolutely necessary, because as a result of the joining of the individual segments that are closed on one side, it is altogether conceivable that some of the parts can be pre-assembled. On segments that can be closed only after the assembly has been completed, it is then possible to install separate closures. These closures can also be positively and non-positively connected with the segments or with the housing by gluing, ultrasonic welding or similar methods. In addition to butt joints, the closures can also be provided with grooves, undercuts or bayonet joints to reduce the assembly time required.
On an injection molded realization made of plastic, the fastening devices in the form of corresponding borings to install the assembled door closer in its intended final location can also be molded using non-cutting methods.
The above-discussed embodiments of the present invention will be described further hereinbelow with reference to the accompanying figures. When the word xe2x80x9cinventionxe2x80x9d is used in this specification, the word xe2x80x9cinventionxe2x80x9d includes xe2x80x9cinventionsxe2x80x9d, that is, the plural of xe2x80x9cinventionxe2x80x9d. By stating xe2x80x9cinventionxe2x80x9d, Applicants do not in any way admit that the present application does not include more than one patentably and non-obviously distinct invention, and maintain that this application may include more than one patentably and non-obviously distinct invention. Applicants hereby assert that the disclosure of this application may include more than one invention, and, in the event that there is more than one invention, that these inventions may be patentable and non-obvious one with respect to the other.